1. Field of the Invention
The present invention relates to an electric oven, and more particularly, to a choking structure for preventing microwave from being leaked through a gap between a door and a case of an electric oven. Especially, the present invention is directed to an improved choking structure of an electric oven, which allows microwave leaked through a gap between a door and a case of the electric oven to be shielded simply with reliability. The choking structure of the present invention can also be applied to any devices having a magnetron for oscillating microwave, not being limited to the electric oven.
2. Description of the Related Art
Generally, a conventional electric oven is a kind of cooking device having a heater for generating heat and a magnetron for generating microwave to heat food. The heat generated by the heater and the microwave generated by the magnetron are transmitted to the food loaded in a cavity of the oven.
The heat generated by the heater functions as a main heat source for cooking while the microwave generated by the magnetron functions as a sub-heat source for the cooking.
The conventional electric oven further includes a case defining the cavity and a door mounted on a front of the case to allow for the load and unload of the food in and from the cavity.
Meanwhile, since the microwave generated from the magnetron is a big health hazard, it is general to provide a microwave shielding structure for preventing the microwave from leaking out of the cavity. However, since the door is mounted on the front of the case while back, left and right sides, and top and bottom of the oven are shielded by the case, it is difficult to perfectly prevent the leakage of the microwave.
That is, the door is designed to be opened for loading and unloading the food and to be closed during the cooking. Therefore, as a microwave shielding structure, a choking portion is formed on a portion where the door contacts the case to prevent the microwave from leaking.
FIG. 1 shows a sectional view of a conventional electric oven, illustrating a portion where a door contacts a case.
Referring to FIG. 1, a conventional electric oven includes a cavity 2 in which food is loaded, a door 1 for selectively enclosing the cavity 2, and a choking portion 3 formed on a portion where the door 1 contacts the cavity 2. The choking portion 3 is extended toward opposite sides on an inner surface of the door 1. The extended portion is bent and extended in another direction such that the microwave discharged in the cavity 2 is shielded by the choking portion 3. Also, the choking portion 3 has a predetermined vertical length A1 and a horizontal length B1. The vertical length A1 and the horizontal length B1 allow a substantial overall extended length (L11+L12) acting as a factor for attenuating microwaves to be determined by a choking camber 35 that is a space between the door 1 and the choking potion 3 and to be once bent.
The function of the choking portion is determined by the substantial entire extended length (L11+L12). That is, the longer the substantial entire extended length (L11+L12), the better the microwave attenuation effect.
Therefore, in order to increase the substantial entire extended length (L11+L12), the vertical and horizontal lengths of the choking portion 3 should be maintained to be greater than predetermined lengths. Therefore, it may be considered that the vertical length A1 is increased while a vertical width of the door 1 is reduced. In this case, since the overall shape of the door 1 is varied, the microwave attenuation effect of the choking portion is also varied. Particularly, the microwave attenuation effect with respect to a specific frequency oscillated in the magnetron is weakened or deteriorated.
In addition, it can be also considered that the horizontal length B1 is increased while a thickness of the door 1 is increased. However, when the thickness of the door 1 is increased, there may be following problems.
First, the increased thickness of the door 1 increases the weight of the door, making it difficult for a user to open and close the door.
Second, the usable space of the cavity 2 is reduced by an increased thickness T1 of the door 1, the food receiving space is reduced.
Third, the increased thickness of the door 1 makes it difficult to define an exterior of the oven while increasing the manufacturing costs.